Device for maintaining a section of a band in lateral position whilst being subjected to a forward movement



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Ircve mior Ja n T/zeve 11 a2 A! for may Patented Dec. 26, 1950 DEVICE FOR MAINTAINING A SECTION OF A BAND IN LATERAL POSITION WHILST BEING SUBJECTED TO A FORWARD MOVEMENT Jean Thvenaz, Sainte-Croix, Switzerland, assignor to Paillard S. A., a corporation of Switzerland Application July '1, 1948, Serial No. 37,376

' In Switzerland July 29, 1947 2 Claims. 1 Various devices are in existence enabling a band subjected to a forward movement to be guided laterally. In a cinematographicapparatus, for example, the lateral position of the band, constituted by the film, during its passagein front of the lens is generally determined by. two similar holding devices placed immediately in front of and immediately after the passage for the film infront of thelens. V

The irregularities in width of commercial bands necessitate the provision of guide members enabling the Widest parts of the band to pass whilst ensuring constant contact of these members with the two lateral edges of the band. I

These guide devices are generally provided with a passage of rectangular cross section, of which the two opposite Walls bear against the edges of the band under the action of a spring which presses one of the two walls, movable, towards the other, which is stationary.

Some manufacturers use as movable wall a spring of suitable shape, others interpose a 'wall between the edge of the film and the spring.

The presence of movable members such as those used up to the present time is, however, inconvenient to the user particularly when placing the film in position. Devices have been provided by .some manufacturers for moving the movable wall outwardly automatically in order to facilitate the engagement of the film in the passage. It will be.

obvious that these latter devices are a source 0 constructional diificulties.

The present invention has for its subject a device for maintaining the lateral position of a band subjected to a forward movement, which has a passage for the band provided with a wall perpendicular to the plane of movement of the band and which is distinguished from known devices by the fact that the second lateral side of the said passage is stationary and inclined relatively to the first in such a manner-as to form a widened or outwardly flaring means being provided for pushing the band or film towards the narrower end or bottom wall of the passage and maintaining one of its edges in permanent contact with a guiding devices located in front of and behind .the passage for the film in front of the lens.

Fig. 2 is a partial front view of the devices shown in Fig. I.

Fig. 3 is a sectional view on the line III-III of Fig. 2.

Figs. 4 to 6 are views similar to Figs. 1 to 3, and refer to a modified form of construction.

In Figs. 1 to 3 of the accompanying drawing, F indicates a film passing around a first spool I then forming an entry loop 3, before passing into the guiding and holding devices, then through the passage 4 which is provided with a window located on the optical axis of the lens 5; passes into the guiding and holding members, forms an outlet loop 6 before passing finally on to a second spool 2.

The device for holding in lateral position the section of the film located in front of the window of the passage 4 located in the optical axis of the lens is provided with a passage P of which one of the lateral sides is formed by a stationary wall 9 located in a plane perpendicular to the transverse plane a of the passage and to the focal plane of the lens, that is to say perpendicular to the plane of the film during its passage in front of the lens. The second lateral side of the passage is formed by the generating line b of the envelope of a conical member l0 located in the transverse plane a. As shown in the drawing,

the generating line b is so inclined relatively to the wall 9 so as to form with the latter a widened passage P. A support I2 is provided at the base of the wall 9 for fixing the position in depth of the film in the passage P. i The distance separating the wall 9 of the generating line b at the height of the support I2 is selected equal to the nominal width of the film.

.The device for maintaining the lateral position of the film shown in the drawing is also provided with members for guiding the film, defining for the latter a section of non-linear travel ex- .tending from opposite sides of the passage P and tending to so deform the film resiliently that its natural elasticity automatically tends to hold its lateral edges in contact with the two sides of the passage P.

The guide members are formed by two supports ll, [3 located on opposite sides of the passage P'. As shown in Fig. 1 the two supports of the film define with the support [2 a non-linear path, the support l2 defining the bottom of the passage P, being located outside the plane defined by the supports H and I3 or outside the plane at which the film is simultaneously 3 tangential to the height of each of these two supports.

The operation of the device described is as follows: When the film F is placed in its track between the spools l and 2 it assumes, seen in profile, approximately the shape shown in Fig. 1. The film leaving the spool I forms an entry loop 3 and its natural elasticity tends to hold it in constant contact with the supporting surface II. In the form of construction shown, this supporting surface is provided with two flats located in the same plane parallel to the focal plane of the lens. However in a modified form of construction of the device described, the bearing surface may only :be provided with a sing-1e fiat or on the contrary more than two flats. The supporting surface II is located approximately in the same plane as the supporting face I3 at the inlet to the passage 4. On the contrary the support I2 which defines the bottom of the passage P is located in front of the plane defined by the supporting faces l I and I3, that is to say in front of the tangential plane e, so that on the section of travel located between these two supporting faces, the film F is deformed resiliently as shown in Fig. 1. Consequently the natural elasticity of the film tends to apply one of its edges against the support I2 and to hold its other lateral edge in contact with the generating line b, forming one of the lateral sides of the passage P. This edge of the film applies a resilient thrust I located in the transverse plane a and perpendicular to the plane of the film. As shown in Fig. 2 this resilient thrust f is decomposed into a force m perpendicular to the generating line b and a force 1 located in the plane of the film and acting on the latter. On examination of Fig. 2 it will be seen that the force p tends to hold the second lateral edge of the film in contact with the wall 9 and thus to hold the film always in the same lateral position.

As the lateral guide it provided by the inclined generating line b is fixed rigidly on the framework of the apparatus, while the Wall 9 may be provided in treated metal, having a very great hardness of surface so that it is possible to completely avoid its wear. Similarly the three supports II, I2, I3 are secured rigidly to the framework of the apparatus and may be formed of a treated metal having a hardness of surface sufficient to avoid any wear due to friction of the film. All the surfaces against which the film r-ubs are polished so as to reduce friction.

One of the great advantages presented by the device described relatively to known devices, is the fact that it is not provided with any movable member and that the lateral thrust 12 applied to the film is produced by the natural elasticity of the latter. It thus follows that the lateral edge of the film is held automatically in constant contact with the wall 9 and that consequently the film always retains the same well defined and precise lateral position.

As shown in Fig. l of the accompanying drawing two devices for maintaining the lateral. position of the film, exactly similar to one another, are located on oppositesides of the passage 4 so as to fix the position of the film when entering and leaving this. and thus maintainin the entire section of the film located between these two points in the desired lateral position.

In the modified form of construction shown in Figs. 4 to 6 the installations provided with a band Fpassing around a spool I into a passage P. 211%.

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in front of a lens 5, and finally through a passage P before being Wound on a second spool 2.

Each passage P is provided with a lateral wall 9 located perpendicularly to the. plane of the band during its passage in front 01' the lens and parallel to the direction of feed of the band. At the bottom of the wall is located a support I2 defining the position in depth of one of the lateral edges of the band engaged in the passage P. The second side of the passage is formed by a wall I; inclined relatively to the wall 9 and parallel to the direction of feed of the film. The walls 9 and b thus define a passage of widened shape from its base defined by the support I2. In this modified form of construction the support I I is omitted, and the support I2 is located outside the plane in which is located the section of band placed in front of the lens.

As in the construction described with refer ence to Figs. 1 to 3, the natural elasticity of the band tends, on the one hand, to hold the edges thereof in permanent contact with the support I2, and on the other hand the two lateral edges of the band in contact with the walls 9 and b. In fact, by reason of the natural elasticity of the band, this forms a loop 3, and it sufiices to cause the two lateral edges of the band to be maintained in a permanent manner in contact with the walls 9 and b, for the support I2, which defines the bottom of the passage P, to be located in front of the plane defined by the passage 4.

It will be understood that the device described may be applied for guiding any type of band, such as bands of paper or steel bearing inscriptions, phonograms etc., which are to pass in front of a lens reproducing and recording device of mechenical, optical, electrical, electro-magnetic or cathode ray type.

It will be understood that this device may be applied directly in its constructional details to the type of band to be guided and to the material of which this is composed.

When the section of band passing into the passages P, has exactly the nominal width, it slides on a plane perpendicular to the axis of the lens and defined by the support I2. When on the contrary the width of the band has deviations relatively to the nominal value, the band continues to bear by one of its edges against the support I2 and to remain in contact at its two edges with the two sides of the passages. It thus follows that the plane of the film is then slightly inclined relatively to the plane perpendicular to the axis of the lens 5, the edge of the band in contact with the inclined wall b may be higher or lower than the support II. The plane of the section under consideration is thus no longer rigourously perpendicular to the optical axis, whilst the passage 4 maintains the section passing in front or the lens in a plane rigourously perpendicular to the axis of the lens.

In the case in which the band has a longitudinal elasticity lnsufilcient for permanently maintaining one of its lateral edges in permanent con.- tact with the support I2, it is possible, for example, to provide a resilient finger formed by a blade spring acting on the said edge of the band and holding it permanently in contact with. the said support. In practice it has been found that the transverse rigidity of. the bands used is always sufficient for ensuring then permanent contact of the two lateral edges thereof with the lateral walls of the passage P.

I claim:

1. n combination with a lens device having a passage for a band such as a film and two spools for said film, one of said spools being in advance of said passage and the other beyond said passage and means moving said fihn, one of the sides of said passage being defined by a lateral stationary wall perpendicular to the transverse plane of the passage, a second side for said passage, said second side being stationary and inclined relatively to said first side, a fixed support rigid with the inner lower side of the first passage wall and engaging the band adjacent an edge thereof, and guide means for said band and having a band engaging planar surface of a" height less than that of the fixed support, said guide means serving to direct said band toward said passage and to maintain one of the edges of said band in permanent contact with said sup port, said support fixing the position in depth of said one edge of said band in said passage and} automatically maintaining the two edges of said" sides of said passage being defined by a lateral stationary wall perpendicular to the transverse plane of the passage, a second side for said passage, said second side being stationary and in- Ls'aid one edge of said band in said passage and automatically maintaining the two edges of said band in contact with the two sides of said passage, the provision of two pairs of spaced supports, one pair of said spaced support located in band in contact with the two sides of said passage, and wherein said means are formed by a' guide passage for guiding said band, a lens in said lens device, said band being guided in front of said lens by said guide passage, said guide passage being so located that in a tangential plane said band at the height of a loop formed in advance of the said passage and at the top of the said passage, passes above the end of the passage defined by said first mentioned support in such a manner that the natural elasticity of the band automatically maintains its two lateral.

edges in permanent contact with the two lateral sides of said passage.

2. In combination with a lens device having a passage for a band such as a film and two spools for said film, one of said spools being in advance of said passage and the other beyond said passage and means moving said film, one of the advance of a passage in front of the lens, and

the second pair beyond said passage, a stationary wall with a support and conical member located between one pair of supports and one end of said passage, a second stationary wall with a support and a second conical member located between the other end of the passage and the second pair of supports.

JEAN THEVENAZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,229,924 Howell Jan. 28, 1941 2,350,780 Lechleitner June 6, 1944 2,425,217 Wienke Aug. 5, 1947 

